/*
Script: Fx.Sort.js
	Defines Fx.Sort, a class that reorders lists with a transition.

License:
	http://www.clientcide.com/wiki/cnet-libraries#license
*/
Fx.Sort = new Class({
	Extends: Fx.Elements,
	options: {
			mode: 'vertical' //or 'horizontal'
	},
	initialize: function(elements, options){
			this.parent(elements, options);
			//set the position of each element to relative
			this.elements.each(function(el){
					if(el.getStyle('position') == 'static') el.setStyle('position', 'relative');
			});
			this.setDefaultOrder();
	},
	setDefaultOrder: function(){
			this.currentOrder = this.elements.map(function(el, index){
				return index;
			});
	},
	sort: function(newOrder){
		if($type(newOrder) != 'array') return false;
		var top = 0;
		var left = 0;
		var zero = {};
		var vert = this.options.mode == "vertical";
		//calculate the current location of all the elements
		var current = this.elements.map(function(el, index){
			var size = el.getComputedSize({styles:['border','padding','margin']});
			var val;
			if(vert) {
				val =	{
					top: top,
					margin: size['margin-top'],
					height: size.totalHeight
				};
				top += val.height - size['margin-top'];
			} else {
				val = {
					left: left,
					margin: size['margin-left'],
					width: size.totalWidth
				};
				left += val.width;
			}
			var plain = vert?'top':'left';
			zero[index]={};
			var start = el.getStyle(plain).toInt();
			zero[index][plain] = ($chk(start))?start:0;
			return val;
		}, this);
		this.set(zero);
		//if the array passed in is not the same size as
		//the amount of elements we have, fill it in
		//or cut it short
		newOrder = newOrder.map(function(i){ return i.toInt() });
		if (newOrder.length != this.elements.length){
			this.currentOrder.each(function(index) {
				if(!newOrder.contains(index)) newOrder.push(index);
			});
			if(newOrder.length > this.elements.length) {
				newOrder.splice(this.elements.length-1, newOrder.length-this.elements.length);
			}
		}
		var top = 0;
		var left = 0;
		var margin = 0;
		var next = {};
		//calculate the new location of each item
		newOrder.each(function(item, index){
			var newPos = {};
			if(vert) {
					newPos.top = top - current[item].top - margin;
					top += current[item].height;
			} else {
					newPos.left = left - current[item].left;	
					left += current[item].width;
			}
			margin = margin + current[item].margin;
			next[item]=newPos;
		}, this);
		var mapped = {};
		$A(newOrder).sort().each(function(index){
			mapped[index] = next[index];
		});
		//store the current order
		//execute the effect
		this.start(mapped);
		this.currentOrder = newOrder;
		return this;
	},
	rearrangeDOM: function(newOrder){
		newOrder = newOrder || this.currentOrder;
		var parent = this.elements[0].getParent();
		var rearranged = [];
		this.elements.setStyle('opacity', 0);
		//move each element and store the new default order
		newOrder.each(function(index) {
			rearranged.push(this.elements[index].inject(parent).setStyles({
				top: 0,
				left: 0
			}));
		}, this);
		this.elements.setStyle('opacity', 1);
		this.elements = $$(rearranged);
		this.setDefaultOrder();
		return this;
	},
	getDefaultOrder: function(){
		return this.elements.map(function(el, index) {
			return index;
		})
	},
	forward: function(){
		return this.sort(this.getDefaultOrder());
	},
	backward: function(){
		return this.sort(this.getDefaultOrder().reverse());
	},
	reverse: function(){
		return this.sort(this.currentOrder.reverse());
	},
	sortByElements: function(elements){
		return this.sort(elements.map(function(el){
			return this.elements.indexOf(el);
		}));
	},
	swap: function(one, two) {
		if($type(one) == 'element') {
			one = this.elements.indexOf(one);
			two = this.elements.indexOf(two);
		}
		var indexOne = this.currentOrder.indexOf(one);
		var indexTwo = this.currentOrder.indexOf(two);
		var newOrder = $A(this.currentOrder);
		newOrder[indexOne] = two;
		newOrder[indexTwo] = one;
		this.sort(newOrder);
	}
});
